在pH7.0的Britton—Robinson(B-R)缓冲溶液中用电化学分析方法研究了孔雀石绿(MG)与鲱鱼精ds—DNA的相互作用。循环伏安法表明,MG在-1.0~+1.5V(vs.SCE)范围内有3个氧化还原峰。加入双链DNA后,由于MG与DNA相互作用,使MG在+0.547V处的氧化峰电流明显降低,而峰电位基本没有改变。优化了结合反应条件,在最佳条件下,MG氧化峰电流的下降值同DNA的浓度在10.0~100.0mg·L^-1范围内呈良好线性关系,线性关系方程为△ip(μA)=0.066+0.0096c(mg·L^-1),检测限(3σ)为6.0mg·L^-1。通过DNA加入前后峰电流的变化,可计算出MG与DNA结合比n(MG):n(DNA)=2:1,结合常数为5.67×10^8。
The interaction of malachite green (MG) with Herring Sperm double-stranded DNA (ds-DNA) in a Britton-Robinson (B-R) buffer solution of pH=7.0 was investigated by electrochemical method. The result of cyclic voltammetry showed that malachite green had three redox peaks from - 1.0 V to + 1.5 V(vs. SCE). The oxidative peak current at +0. 547 V was decreased after the addition of double-stranded DNA (dsDNA) whereas without the movement of peak potential. The decrease of the peak current was directly proportional to DNA concentration in the range of 10.0-100.0 mg· L^-1. The regression equation was △ip(μA)=0. 066+0. 009 6c(mg · L^-1) and the detection limit was 6.0 mg · L^-1 (3σ). It was calculated that the binding ratio of MG : DNA was 2 : 1 and the binding constant was 5.67× 10^8.